Hi mdone,
I never compared the Rockna to the AM. I sold my Denafrips Terminator and bought the AudioMirror Tubadour III SE which I liked better. It was more natural sounding with very nice tone and timbre. Detail and resolution were close.
If you're interested I might be selling mine in a few weeks. My buddy just got an Aries Cerat Kassandra II and I might buy his Mola Mola Tambaqui.
The Tambaqui does sound better than the AM but, it doesn't blow it away and it cost 5 times more. I think the AudioMirror is a steal at that price point, IMHO